Offshore refuges support higher densities and show slower population declines of wintering Ruddy Turnstones Arenaria interpres

ABSTRACT

Capsule: Wintering Ruddy Turnstones Arenaria interpres occur in higher densities and their populations decline less on, or close to, offshore refuges than on mainland sites subject to greater levels of human disturbance.

Aim: To compare wintering densities of Ruddy Turnstones and changes in counts across time from sites with differing levels of human disturbance.

Methods: Long-term counts of Ruddy Turnstones (1998/1999 to 2015/2016) were used from 19 sites (two offshore refuges and 17 mainland sites subject to higher levels of human disturbance) in northeast England. No direct measure of human disturbance was available for our mainland sites; instead we used questionnaires (n?=?690) to understand how far people travelled to visit the coast and then used this distance with human population densities in a buffer around each site as a proxy for human disturbance levels.

Results: After controlling for the extent of their preferred habitat at each site (rocky shore) we found: (i) the closer each of the 19 sites was to the nearest offshore refuge the higher the density of Ruddy Turnstones and (ii) bird counts were stable at the two refuge sites, whereas, on average, counts declined at the 17 mainland sites. However, no relationship was found between Ruddy Turnstone counts from 17 mainland sites and human population densities within differing distances from each site (up to 10?km).

Conclusions: Our work suggests that Ruddy Turnstones made greater use of relatively undisturbed areas (offshore refuges) than those subject to greater disturbance by humans (mainland sites). Although the use of refuges and mainland in our study area was not well known, observations from 11 radio-tagged Ruddy Turnstones suggest that individual birds did use both locations. In a broader context, our work concurs with other studies that highlight the need for refuges with limited or no human access.     

WADERS (CHARADRII) AND OTHER SHOREBIRDS AT CAPE RECIFE,ALGOA BAY,SOUTH AFRICA: SEASONALITY,TRENDS, CONSERVATION,AND RELIABILITY OF SURVEYS

Spearpoint, J. A., Every, B. & Underhill, L. G. 1988. Waders (Charadrii) and other shorebirds at Cape Recife, Algoa Bay, South Africa: seasonality, trends, conservation, and reliability of surveys. Ostrich 59: 166–177.

A total of 126 surveys of waders (Charadrii) and other shorebirds were made along 4 km of shore northwest of Cape Recife. The surveys were conducted bv two observers who counted independently of each other. The variability between observers was least for conspicuous species such as Whitefronted Plover, Blacksmith Plover, African Black Oystercatcher, Whimbrel and Grey Plover, but greatest for cryptic species such as Ringed Plover and for species which formed a minority in mixed flocks such as Curlew Sandpiper and Little Stint. Variability of surveys within years and between years is also considered. Turnstones and Sanderlings were the most abundant waders in summer. Of the Palaearctic waders, Turnstones, Grey Plovers, Sanderlings, Greenshanks and Whimbrels overwintered. In contrast, Ringed Plovers, Curlew Sandpipers, and Little Stints rarely overwintered. Little Egrets, Threebanded Plovers and Water Dikkops occurred mainly in winter. It is recommended that surveys to estimate numbers of Palaearctic waders in summer and winter should be conducted in December, January or February and June or July, respectively. Because of three-year cycles in breeding productivity of certain waders, surveys should be extended over at least three years. There was evidence that waders associated with rocky shores increased in numbers during the study period: this coincided with the erosion of sandy beaches near Cape Recife. Density, biomass and daily field metabolic rates, expressed on an area basis, were similar to those in eastern Scotland. Nine species of tern utilized Cape Recife. It is recommended that the bait-collecting regulations be enforced, that vehicles be prohibited on the beach, and that the tern roost and breeding site be fenced off to create a sanctuary.     

Cover

ON THE COVER Durvillaea antarctica is common in the intertidal zone of the subantarctic, growing on exposed rocky shores (here: Calfuco near Valdivia, Chile). During storm events individuals may end up on nearby beaches or float over large distances due to its highly buoyant tissues. Photograph: Martin Thiel [Vol. 53, No. 1, pp. 70–84]     

Spatial and Temporal Variation in Enterococcal Abundance and Its Relationship to the Microbial Community in Hawaii Beach Sand and Water

Recent studies have reported high levels of fecal indicator enterococci in marine beach sand. This study aimed to determine the spatial and temporal variation of enterococcal abundance and to evaluate its relationships with microbial community parameters in Hawaii beach sand and water. Sampling at 23 beaches on the Island of Oahu detected higher levels of enterococci in beach foreshore sand than in beach water on a mass unit basis. Subsequent 8-week consecutive samplings at two selected beaches (Waialae and Kualoa) consistently detected significantly higher levels of enterococci in backshore sand than in foreshore/nearshore sand and beach water. Comparison between the abundance of enterococci and the microbial communities showed that enterococci correlated significantly with total Vibrio in all beach zones but less significantly with total bacterial density and Escherichia coli. Samples from the different zones of Waialae beach were sequenced by 16S rRNA gene pyrosequencing to determine the microbial community structure and diversity. The backshore sand had a significantly more diverse community and contained different major bacterial populations than the other beach zones, which corresponded to the spatial distribution pattern of enterococcal abundance. Taken together, multiple lines of evidence support the possibility of enterococci as autochthonous members of the microbial community in Hawaii beach sand.     

Influence of Land Use,Nutrients, and Geography on Microbial Communities and Fecal Indicator Abundance at Lake Michigan Beaches

Microbial communities within beach sand play a key role in nutrient cycling and are important to the nearshore ecosystem function. Escherichia coli and enterococci, two common indicators of fecal pollution, have been shown to persist in the beach sand, but little is known about how microbial community assemblages are related to these fecal indicator bacteria (FIB) reservoirs. We examined eight beaches across a geographic gradient and range of land use types and characterized the indigenous community structure in the water and the backshore, berm, and submerged sands. FIB were found at similar levels in sand at beaches adjacent to urban, forested, and agricultural land and in both the berm and backshore. However, there were striking differences in the berm and backshore microbial communities, even within the same beach, reflecting the very different environmental conditions in these beach zones in which FIB can survive. In contrast, the microbial communities in a particular beach zone were similar among beaches, including at beaches on opposite shores of Lake Michigan. The differences in the microbial communities that did exist within a beach zone correlated to nutrient levels, which varied among geographic locations. Total organic carbon and total phosphorus were higher in Wisconsin beach sand than in beach sand from Michigan. Within predominate genera, fine-scale sequence differences could be found that distinguished the populations from the two states, suggesting a biogeographic effect. This work demonstrates that microbial communities are reflective of environmental conditions at freshwater beaches and are able to provide useful information regarding long-term anthropogenic stress.     

Differential effects of native and invasive algal wrack on macrofaunal assemblages inhabiting exposed sandy beaches

Many sandy beaches worldwide receive large amounts of drift seaweed, known as wrack, from offshore algal beds and closer rocky intertidal shores. Despite the important influence of algal wrack on macrofaunal assemblages from different coastal systems, relatively little attention has been paid to the macrofaunal responses in sandy beaches to macrophyte wrack supplies. Algal wrack is a key resource, i.e. for food and/or refuge, for beach invertebrates while its availability can affect diversity and abundance of intertidal animals including shorebirds, but the role of certain types of wrack and its location on the shore has not been examined experimentally to date. In this paper, we use experimental manipulation of two species of brown seaweeds, i.e. artificial wrack patches made up of the native macroalgae Saccorhiza polyschides and the invasive species Sargassum muticum, to test hypotheses about influences on macrofaunal assemblages inhabiting the drift line and supratidal levels of exposed beaches. Results pointed out that different types of wrack deposits were not used uniformly by invertebrates. Nutritional value differed between the two species of wrack. In most cases, the carbohydrates, lipids and organic carbon content were greater in patches of S. muticum than in patches of S. polyschides. Data also provided evidences that nutritional content and microclimatic conditions of wrack deposits, i.e. temperature and humidity, might affect macrofaunal assemblages.     

Physiological and growth responses to water deficits in cultivated strawberry (Fragaria × ananassa) and in one of its progenitors,Fragaria chiloensis

Cultivation of strawberry (Fragaria × ananassa) requires irrigation. Improving crop water use efficiency (WUE) is important for future production. Fragaria chiloensis, a progenitor of cultivated strawberry, grows in sandy soils, and may prove useful in breeding for improved WUE. Little, however, is known about variation in drought tolerance within this species. This research explores drought tolerance in a range of F. chiloensis and F. × ananassa genotypes. Four cultivars of F. × ananassa and four accessions of F. chiloensis were compared when well watered, and when subjected to a water deficit (65% of evapotranspiration). New leaf production, stomatal conductance, and photosynthetic rate were significantly reduced under water deficit, and also significantly differed between genotypes. A significant interaction of genotype and irrigation was found for transpiration rate, leaf area and dry mass, production of runners, predawn water potential, a measure of transpiration efficiency (shoot biomass produced per litre water transpired), and carbon isotope composition, indicating that some genotypes were more severely affected by water deficit than others. The South American F. chiloensis accession ‘Manzanar Alto’ had a similar rate of transpiration to the commercial cultivars, but the remaining (North American) F. chiloensis accessions used far less water than the F. × ananassa. Well-watered F. chiloensis plants used less water than water-limited plants of the F. × ananassa cultivar ‘Florence’. Transpiration efficiency of the F. chiloensis accession ‘BSP14’ was improved by water deficit: this was the only genotype not to show a reduction in leaf area and dry mass under water deficit. Greater drought resistance in three F. chiloensis accessions compared to F. × ananassa results from a conservative vegetative growth strategy, reducing loss of water.     

Evolution of the Northern Rockweed,Fucus distichus,in a Regime of Glacial Cycling: Implications for Benthic Algal Phylogenetics

Northern hemisphere rockweeds (Fucus) are thought to have evolved in the North Pacific and then spread to the North Atlantic following the opening of the Bering Strait. They have dispersed and widely speciated in the North Atlantic and its tributary seas. Fucus distichus is likely near the ancestral member of this genus, and studies have shown that there are several species/subspecies in this complex (i.e. F. evanescens and F. gardneri). We used phylogenetic and haplotype analyses to test the phylogenetic relationships and biogeography of F. distichus. Our data and subsequent analyses demonstrate that, unlike previous studies that lacked samples from an extensive geographical area of the Arctic and Subarctic, there is a distinct Arctic haplotype that is the source of subspecies in both the North Pacific and North Atlantic. Fucus distichus occupies a low tide zone habitat, and in Arctic/Subarctic regions it is adapted to the severe stress of sea ice coverage and disturbance during many months per year. We hypothesize that the very large geographic area of Arctic and Subarctic rocky shores available to this species during interglacials, supported by large Arctic/Subarctic fringe areas as well as unglaciated refugia during glacial cycles, provided a robust population and gene pool (described by the Thermogeographic Model). This gene pool dilutes that of the more fragmented and area-limited Temperate/Boreal area populations when they are brought together during glacial cycles. We suggest that similar subspecies complexes for a variety of Arctic/Subarctic shore biota should be examined further in this context, rather than arbitrarily being split up into numerous species.     

Mortalities caused by off-road vehicles (ORVs) to a key member of sandy beach assemblages,the surf clam <Emphasis Type="Italic">Donax deltoides</Emphasis>

Sandy beaches are prime recreational areas, but human use of beaches is not without ecological consequences. Driving of off-road vehicles on beaches for recreational pursuits is perhaps the physically most severe form of direct anthropogenic disturbance on sandy shores. Potential management and conservation interventions lack, however, data on how sensitive beach species are to vehicle impacts. We therefore experimentally quantified the link between beach traffic and lethal damages caused by vehicles to sandy shore invertebrates, using surf clams (Donax deltoides) as the biological response variable. Although clams had some tolerance against vehicles at low traffic volumes (5 vehicle passes), more than half of them were killed at higher traffic volumes (75 passes) in situations where cars traversed soft sand and turned across the beach face. Overall, both traffic volume and driver behaviour (i.e. straight vs. turning vehicle tracks) determined the incidence of direct crushing of clams under vehicles. Our data demonstrate that recreational use of ORVs is a source of mortality for beach invertebrates, but equally caution against extrapolating impact data from hard-shelled clams to potentially more sensitive soft-bodied species. Robust management interventions that seek to mitigate ecological damage from beach traffic will therefore require information on the functional relationship between the form, intensity and frequency of human disturbance and the biological responses for entire faunal assemblages on sandy shores. Handling editor: T. P. Crowe     

DISPERSAL OF HORMOSIRA BANKSII (PHAEOPHYCEAE) VIA DETACHED FRAGMENTS: REPRODUCTIVE VIABILITY AND LONGEVITY1

Drifting, fertile thalli are well documented to be the primary long‐distance dispersal vector for many marine macroalgae, but little information about reproductive viability of drift is known. This study examined the reproductive viability and longevity of floating fragments of the intertidal Australasian fucoid Hormosira banksii (Turner) Decne. Beach wrack surveys and field experiments were conducted to test the model that long‐distance dispersal is achieved in H. banksii via floating, fertile fronds. High densities of beach wrack fragments were evident during summer compared to autumn. The majority of beach wrack occurred on sandy beaches rather than rocky shores. Both male and female fragments were present in the beach wrack. Detached fronds were capable of releasing gametes up to 8 weeks after detachment. Beach wrack produced high fertilization rates and recruited successfully onto artificial panels. Results suggest that detached fragments are reproductively viable and that floating, fertile fronds may be an important mechanism for facilitating long‐distance dispersal in this species. Nevertheless, the frequency of fronds reaching a suitable habitat and contributing to gene flow between populations, or colonizing new populations, may not be proportional to the total density of beach wrack.     

Spectral reflectances of three tiger beetle subspecies (Neocicindela perhispida): Correlations with their habitat substrate

Abstract

The coloration and cuticular reflec-tivity of the three subspecies of the tiger beetle Neocicindela perhispida, that occur along coastal beaches of the North Island of New Zealand, were examined. The hardened forewings (elytra) of all three subspecies exhibited colour patterns that matched the sand of their respective beach habitats. The dark N. p. campbelli, which occurs on black ironsand beaches, absorbed significantly higher amounts of solar radiation than N. p. giveni whose white elytra blended well with the white quartz sands on which it occurred. The mottled N. p. perhispida, which inhabits yellowish-brown beaches, exhibited reflectivities generally intermediate to these two extremes.     

Floral biology of Echinopsis chiloensis ssp. chiloensis (Cactaceae): Evidence for a mixed pollination syndrome

In this study the flower biology of Echinopsis chiloensis ssp. chiloensis, a columnar cactus occurring in Central Chile, is investigated, in particular its pollination syndrome, its visitors, their frequencies and behaviors and their pollination efficiencies. As statements on floral anthesis of this species are contradictory, this study also intended to elucidate both its beginning and duration. A pollinator exclusion study of a total of 162 flowers from 12 plants was conducted at one of the two study sites. Fruit and seed production as well as seed viability were documented to evaluate pollinator efficiencies.     

Revision of Stenotaphrum (Gramineae: Paniceae) with attention to its historical geography

Seven species are recognized, of whichStenotaphrum helferi, native to forested streambanks in southeastern Asia, is considered the most primitive. Four species are restricted to tropical islands and coasts of the western Indian Ocean ; one of these, 5.dimidiatum, may have had its range within the region expanded by planting as a pasture grass during the early colonial period.Stenotaphrum micranthum is a naturally wide-ranging beach pioneer in both the tropical Pacific and Indian Oceans, particularly on small, remote islands. The last species,S. secundatum, includes fertile diploids and sterile polyploids. The common diploid race has been found since the early days of botanical exploration as a seashore pioneer on both sides of the Atlantic; in West Africa it is strictly tropical, but in the New World it ranges from the Carolinas and Bermuda to Argentina; early Pacific expeditions also found it in Hawaii and the Australian region ; this race has been taken inland as a lawn grass and spread locally as a weed. A triploid clone of this species, originally confined to the Cape of Good Hope region, has recently been planted and naturalized in Australia, various Pacific islands, and North America; another aberrant Southern Hemisphere race has become naturalized in the Mediterranean region.     

Offshore refuges support higher densities and show slower population declines of wintering Ruddy Turnstones Arenaria interpres: a response

ABSTRACT

In this reply, we confirm that the results of the original paper are robust and that our conclusions were correct: densities of Ruddy Turnstones Arenaria interpres were lower on sites located further from undisturbed refuges. There are two points of learning here: (i) taking the findings of a paper based purely on what is published is normal but there is an unpublished iterative process for analysis that is often hidden from a reader (described here), so we refute that our results were caused by chance; (ii) we published a result based on an incorrect method in the revision process. We hope that other researchers involved in long-term projects involving large and complex datasets can learn from our mistake, as we will endeavour to do.     

Genetics and taxonomy of Chilean smooth-shelled mussels, Mytilus spp. (Bivalvia: Mytilidae)

It has been previously established that native smooth-shelled mussels in southern South America possess close evolutionary affinities with Northern-Hemisphere Mytilus edulis L. 1758 (McDonald et al. (1991) [5]). This result has since been challenged by authors claiming that Chilean mussels should be considered a local subspecies of M. galloprovincialis Lmk. 1819. Moreover, morphological, physiological, ecotoxicological and molecular genetic studies on Chilean smooth-shelled mussels still frequently refer to ‘M. chilensis’ Hupé 1854, even though the previous discovery of alien M. galloprovincialis and considerable heterogeneity in shell morphology among samples collected along the Chilean shores raise concerns that different Mytilus spp. species might have been included under ‘M. chilensis’. Here we reviewed the molecular and morphological data available on smooth-shelled mussels from Chile in an attempt to clarify both their genetic composition and their taxonomic status. Using multivariate analysis on sample × allozyme-frequency matrices, we confirmed the widespread occurrence of the Southern-Hemisphere form of M. edulis along the shores from the North Patagonia region of Chile to the southern tip of the South American continent. The populations sampled in southern central Chile showed some evidence of slight introgression from Southern-Hemisphere M. galloprovincialis. Morphological characterization of a sample from Dichato in southern central Chile was consistent with its previous genetic identification as Mediterranean M. galloprovincialis. The occurrence of Southern-Hemisphere M. galloprovincialis in Punta Arenas at the southern tip of the South American continent was also reported. Southern-Hemisphere M. edulis, including native Chilean smooth-shelled Mytilus, should be assigned subspecific rank and named M. edulis platensis d’Orbigny 1846.     

Taxonomic composition and distribution of the echinoderms associations in the littoral ecosystems from the Colombian Pacific

This paper examines published information and gray literature about taxonomy and ecology of echinoderm species of the Colombian Pacific Coast. Unpublished collection data of specimens kept in the Marine Sciences Museum of the University of Valle are also considered. Sixty-six species are found in coastal ecosystems and shallow bottoms of ten geographical, coastal and insular localities of the Pacific coast of Colombia. Main habitats having echinoderms are: rocky cliffs and shores, coral reefs, sand beaches, mud substrates, mangroves, and shallow bottoms of mud, sand, gravel and rocks. Regular Echinoidea and Asteroidea are the most diverse and abundant groups, mainly in subtidal rocky shallow bottoms and coral reefs. Ophiuroidea are abundant below rocky boulders. Irregular Echinoidea are abundant on sand beaches. The relatively high number of species shows that this geographical area presents a high diversity of echinoderms compared with other tropical shallow and littoral zones of the world. Rocky substrates and coral reefs are the ecosystems with the highest numbers of echinoderm species and individuals. A conservation status assessment is difficult because the lack of periodical sampling and few data about deep zones. In general, the species reported in the last 25 years, have not experimented important changes in their populations, although in some specific places, populations may decrease because human activities in coastal areas increase sedimentation rates change some rocky substrates to mud or sand.     

Sub-lethal effects of off-road vehicles (ORVs) on surf clams on sandy beaches

Ecological impacts of vehicle traffic are a significant environmental management issue on many sandy shores. Impacts usually focus on lethal effects of vehicles to organisms, but sub-lethal effects which could reduce the fitness of macrofauna populations are equally possible but unknown. Consequently, we measured changes in body condition and burrowing performance of the beach clam Donax deltoides subjected to vehicle traffic on sandy shores in eastern Australia. Body mass index of clams on beaches open to traffic was 16% lower, but gonadosomatic index and relative valve thickness were not consistently linked to vehicle access to beaches. By contrast, off-road vehicles significantly impaired the burrowing performance of clams. After experimental exposure to ORV traffic (30 passes) and dislodgement from the sediment, the time taken for clams to re-bury into the sand doubled irrespective of the vehicle weight used. Because burrowing is such a critical function in the behavioural repertoire of sandy beach animals, the traffic-induced changes to organisms' performance found in this study may increase mortality by causing displacement to less favourable habitats by swash, and by intensifying the risk of predation and desiccation. When assessing the ecological impacts of vehicles on beach fauna, it is thus important to consider both lethal and sub-lethal effects.     

Phylogenetic relationships of the ubiquitous coral reef crab subfamily Chlorodiellinae (Decapoda,Brachyura, Xanthidae)

The xanthid subfamily Chlorodiellinae is one of the most ubiquitous coral reef crab taxa in the Indo‐West Pacific region. Many species are common in coral rubble and rocky shores from Hawaii to eastern Africa, often dominating reef cryptofauna in terms of biomass. Phylogenetic analyses of mitochondrial (COX1, 12S rRNA and 16S rRNA) and nuclear (histone H3) gene sequences of 202 specimens indicate that the Chlorodiellinae is polyphyletic as presently defined. Three genera, Pilodius, Cyclodius and Chlorodiella, and two previously undescribed lineages were recovered as a well‐supported clade. In combination with morphological data, the subfamily is redefined and restricted to this clade. Two new genera, Soliella gen. n., and Luniella gen. n., are described based on features of the carapace, male thoracic sternum and male gonopods. The remaining chlorodielline genera and members of the Etisinae, a subfamily with supposedly close morphological affinities to the Chlorodiellinae, were recovered at various positions throughout the xanthid phylogeny, although with relatively low support values. These results reiterate the unresolved status of xanthid subfamilial relationships, but nevertheless provide progress for xanthid systematics.     

Fungi colonizing hair-baits from three coastal beaches of Mexico

The abundance of hair-bait colonizing fungi was investigated on the beaches of Caracoles, Mocambo, and lcacos, located on the coasts of the Caribbean Sea, Gulf of Mexico and Pacific Ocean, respectively. On each beach a sample of sandy soil was collected. The samples were analyzed by two selective isolation methods for keratinophilic fungi resulting in a total of 544 occurrences. A total of 17 species was found, of which 4 were ascomycetes and 13 hyphomycetes.Gymnascella dankaliensis andAspergillus terreus were the most abundant.Arthroderma curreyi andChrysosporium tropicum were found in low percentages in this survey. From the three beaches sampled, Icacos beach, on the Pacific Ocean coast had the highest number of isolated species.